I suddenly felt unutterably depressed.
我突然感到莫名的惆悵。
柯林斯例句
These two felt unutterably bound to each other.
這兩個(gè)人都覺(jué)得極其難舍難分.
辭典例句
"she was looking very young tonight, and, as usual, indescribably beautiful, in a simple strapless dress of a green and white silky cotton"